


Acidosis

by Frostberry



Category: Naruto
Genre: Fourth Shinobi War, M/M, Time Travel
Language: English
Status: Completed
Published: 2018-07-04
Updated: 2018-12-21
Packaged: 2019-06-05 11:37:24
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 4
Words: 4,108
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15169916
Author URL: https://archiveofourown.org/users/Frostberry/pseuds/Frostberry
Summary: Causes of metabolic acidosis can include build-up of body toxins, kidney failure and ingestion of certain drugs or toxins, such as methanol or large doses of aspirin. Being stuck in a dimension of Kaguya Otsutsuki’s is the worst. Luckily, Kakuzu knows how to past the time. Hidan x Kakuzu





	1. Chapter 1

**** “...I can’t believe we have to wait for Itachi and  _ Tobi,  _ out of all fucking people, to pull us out this this bullshit dimension...” Hidan tried to sidestep the acidic stream, to find his sandals melting into it. “Even worse than finding out that some old geezer manipulated Tobi into believing he’s doing some good shit for the world.” 

“Uchiha Madara is from my generation.” stated Kakuzu. 

“Yeah, and you’re an old fucking geezer,” Hidan shook off his sandal just as it fell into pieces. Spots of acid burned into his hand and he winced. “Fuck this. Is there  _ any way  _ we can communicate with them to get us the fuck out of this desert?” 

Kakuzu shook his head. The only people alive at the moment were the Akatsuki, who had been hell-bent on world domination. Until the Fourth Shinobi War happened, they realised Tobi’s actual plans, then he decided turn his back on Uchiha Madara at the last minute. 

Pain and Konan were the first to perish when the Ten Tails went wild. Deidara and Sasori were next. Sasori’s puppets shattering under the pressure of the beast ball. Deidara’s attempt at blowing himself up while under the shield that protected everyone else from the Ten Tails did work for only a few precious minutes. When the God Tree grew and took everyone as its seed, it took Orochimaru. Zetsu turned out to be manipulating the world from the start. So that left Kisame, Hidan, Kakuzu, Itachi and Tobi. 

“Hoshigaki was also sucked into a different dimension,” said Hidan. “That means Itachi will go and get him first. Oh  _ god  _ what if we are stuck here forever?” 

Kakuzu didn’t reply, as he had no idea. He might have been old, knew how to strategize and outmatch his opponents, but he felt like Kaguya was more of a job for Itachi and Tobi. Jashin would probably kill Hidan if he went after Kaguya, as Jashin was originally a Otsutsuki God.  _ Sacrificing himself  _ instead of  _ sacrificing other people _ ? Not exactly something Hidan would do, and he still wasn’t considering it. Kakuzu on the other hand would probably sacrifice himself at first chance. 

“We’re useless now,” Kakuzu said. “The only way to get rid of Kaguya is killing her. If you aren’t even going to be able to get near her to get some blood, then what is the point of you?” 

Hidan turned his back, and shrugged. “I dunno.” He sat down on a rock. “I’m just someone you can’t get rid of.” 

“At least I  _ can  _ help.” 

“Yeah, strangle her with my big detachable dick, hurr durr.” 

Hidan had been going on about ‘Kakuzu’s detachable dick’ for a while. His theory was that Kakuzu once said ‘All five of my limbs can come off’ at an opponent once, which made Hidan conclude that Kakuzu  _ did  _ have a sense of humour. Even if it was just immature for a cynical tsundere like Kakuzu. 

Hidan’s sense of humour was just strange. But then again, people from Yugakure were just stupid in general. After sacrificing four Konoha chunnin outside a bounty station, Hidan went inside and slaughtered the bounty collector, Zangei, ‘Five sacrifices today, for each of Kakuzu’s limbs’. Kakuzu then proceeded to make Hidan clean the room, so Hidan cleaned it with bleach. He drank half of it and offered some to Kakuzu. 

“Watcha smirking at? Thinking about your five metre long dick to shove down Kaguya’s throat?” 

Kakuzu sat down on a rock, away from the acid. He looked up at the pink, sunsetty-like sky, even though he knew it was nearly dawn back in the real world. He scooped up some of the orange dust to look more closely at it. “You drinking bleach.” 

“Eh? That was ages ago.” Hidan sat down too. He now only had one sandal, a hand rotting away at the wrist because of the acid. “That was a good sacrificing day. Then you got Hatake Kakashi like, a few days later. That was pretty good.” He frowned at his hand, the bone showing and sparkling clean as it was eaten away. The sinew from the muscle melted and dripped onto the rocks, smoking away before disintegrating. “First time we met the Nine-Tails that day. Turns out Hatake was his sensei! I would have never fuckin’ guessed.” 

The Nine-Tails was defeated by Pain months later. Hidan had seen him on the battlefield reincarnated only a few hours ago along with the other Jinchuriki.

While they sat down, Kakuzu attended to his own injuries. He had to stitch up his own stitches, which had been ripped apart by a reincarnated Isumo and Kotestu. They looked like little plaits, Hidan had noticed. Getting out his first aid packet, he wiped the blood away with a wipe, applied antiseptic and put a bandage on a particulary nasty wound from trying to get out of the way of the rasengan.

Hidan on the other hand, pulled out a molar and spat out the remaining blood from his gums. 

“I don’t think I’m able to fix your hand,” said Kakuzu, watching as Hidan threw the molar into the acidic stream. It fizzled and dissolved, like a vitamin tablet. 

“It’ll come back. Give it time.” 

“If Itachi and Obito come back, you can’t fight.” 

Hidan shrugged. If only he knew what he was getting into. 

 


	2. Ennui

**Summary for the Chapter:**

> \- Ennui -  
> \- A Feeling of listlessness from lack of excitement. -

Vomit splashed Kakuzu’s shoes, seeping and burning into the cracks between his toes. Kakuzu didn’t leapt out the way, as he was used to being covered in filth, which he had been for the last twenty four hours since the Fourth Shinobi War began. 

Hidan pressed his forehead onto Kakuzu’s knee, who was sitting down on a rock, away from the stream of acid. “Fucking… ugh.” He’d obviously vomited from pain; Kakuzu knew Hidan had an extreme tolerance to pain, only when he was in his Cursed form. However, acid had eaten away to his shoulder before Kakuzu sliced his arm off to stop it spreading so  Hidan wouldn't turn into a melting pool of bones. 

“How long have we fucking been here?” 

Kakuzu checked his pocket watch. The magnet which moved the hands around the clock had stopped moving; around the time they had been thrown into this dimension, which was 2:23am. He put it back, and Hidan’s forehead became slimy with sweat as he did so. He groaned some more, and threw up again, soupy and hot, this time the vomit squeezing into the toes like he had squished his sandals into some mud. He wanted to pat Hidan on the head, as a gesture that he was almost sorry for his illness. “Don’t know. Time might be different to what’s happening on the outside.” 

“So what if we’ve been here like, fifty years already?” 

“I don’t think so,” said Kakuzu, looking up into the pink sky. “Kaguya said she had been trapped a long time. Thousands of years. And she had.” 

Hidan made a nonchalant noise, breathed heavily and finally got up. His arm was slowly re-growing, like a plant that had been pruned. “I think we’ve been here like… two hours. If I had a damn radio I’d let them know that  _ we  _ are also part of this fight and  _ hurry the fuck up _ .” 

“You have no idea of war,” said Kakuzu, “You have no patience. Patience and knowing when to strike is the key to winning a fight. Being impatient is a quality that surely should have made you fail your chunnin exams.” 

“I’ve been patient.” 

“People who are impatient say those words all the time,” Kakuzu pointed out. Hidan threw his body back into the sand, looking up in the sunless sky, a forever pale pink. He looked like he was going to do snow angels, but just laid there instead, using his normal hand to sift his fingers through the soft red sand. “Obito and Madara spent years on the plan to throw everyone into an infinite tsukuyomi.”

“What would you be doing if you were in the infinite tsukuyomi?” Hidan was still watching the sky. He looked peaceful; and Kakuzu’s first thought was being in a peaceful place with no war, somewhere with Hidan. “...Never mind. Probably just you being a Pimp or something.” 

“And you would be in a world where Jashinism is the major religion,” said Kakuzu. 

“True ‘dat.” 

There was silence, until Kakuzu decided to break it. “But once you sacrifice everyone in the world, what will happen then?” 

Hidan frowned. “I don’t know.” 

“What do you think is happening now then, Hidan?” 

“The entire world has been sacrificed.” 

Now he understood. Jashin, being an Ootsutsuki, would have fully supported the war.  _ Did this mean Hidan was finally gaining some common sense?   _ Kakuzu wondered.  _ After all this time, the man actually had one smart bone in his body? _

Hidan shrugged. “When I am the last one left, Jashin will turn on me.” He paused. “Yeah, I don’t care.” 

Kakuzu rolled his eyes. “I honestly thought you were being philosophical, almost intelligent.” 

“Nah, I see it how it is. Live life in the fast lane.” 

The sea of acid, which was washing downstream near them, was starting to move now. “Hidan,” said Kakuzu quietly, getting up from the rock. “We need to leave.” 

“We can’t fucking go anywhere.” 

There was crackles, like crunching dried rice puffs, the green and yellow slime that was lazily going away from them was bubbling,  _ blip blip blip  _ and  _ gug gug gug _ . 

“Away from the acid,” Kakuzu ordered, as a geyser burst from the stream. “Or you’ll die.” 

Usually, Hidan’s retort was that he couldn’t fucking die, so shut the fuck up, but after one splash of acid disintegrated his bones, he obeyed Kakuzu’s orders. 

The geyser of acid was getting bigger, and they moved away, but that was then it became a full blown tsunami, threatening to shower them. 

“Oh, fuck.” 

 


	3. Hiraeth

**Summary for the Chapter:**

> A homesickness for a home you can't return to, or that never was.

**\- Chapter 3:** **Hiraeth**

**A homesickness for a home you can't return to, or that never was. -**

 

Kakuzu was now staring at Hidan’s skeleton, his head being the only thing on him. The rest of him was literally… a skeleton. The meaty bit where the next was swallowed spit, leaking out into the collar bones. 

“Did we get out okay?” Hidan said, his wet lips picking up grains of orange dirt from his position on the ground. 

“I did,” said Kakuzu gruffly. “You’re too slow.” He then nodded at Hidan’s skeleton, which was on the ground. Sinew and muscle poked out of his spine, and he got up. 

“Fuck! I’m a fucking skeleton!” 

It was totally surreal, the bones trying to pick themselves up from the weight of Hidan getting up suddenly, then they collapsed again. They didn’t go into a pile of bones though, as if Hidan’s body was connected by chakra that kept the shape intact. It reminded Kakuzu of Sasori’s chakra strings. 

There was a call out from somewhere, “Kakuzu! Hidan!” 

“Tobi-” A shower of purple emerged, as a grey haired Obito appeared, eyes red and blood dripping down his cheeks. “Come here-” 

Kakuzu suddenly leapt towards it, with Hidan shrieking behind him that he couldn’t move. A second later, the portal suddenly closed, only to be opened with Obito not there and a black static mass swarming out.

Millions of flies engulfed Kakuzu quickly; he pulled at his Akatsuki cloak to tear a part of it off to use as a makeshift handkerchief around his mouth, as he lost his mask just before they were transported here. “What kind of jutsu is this!?” The buzzing became louder and louder, flies cramming themselves into Hidan’s mouth and crawling down his windpipe while his body struggled to mend itself with the diminishing chakra he had left. 

“A summoning jutsu,” said Kakuzu thickly. He made a few hand signs quickly, using the only heart’s chakra he had left; his original one. Using his water and earth elements, he used a a very basic mud jutsu to engulf the flies, their tiny little wings being drenched in dirt and sticking to it. Their little legs moved helplessly in the air. Kakuzu spat out the remaining ones as the brown sludge, already encrusted with dead flies, pulled Hidan away with mud and his own arms, which he detached to get to him. Hidan’s body, knowing how much danger he was in, had already returned his body organs and the skin on his feet and hands were showing as he mended rapidly.

Hidan made several coughing sounds, fly mush trickling out of his mouth. Even though he looked as if he had been skinned, he seemed to be okay to get up by himself. “What the fuck was that.” 

“Most likely a summoning jutsu of Kaguya’s,” Kakuzu suggested. His boots made a squelch as he got out of the mud. 

“Gross.” He looked up at Kakuzu. “Tobi knows we are here… is he gonna come and get us?” 

***

Kakuzu split open his last remaining raton pack, with its soggy rice and crackers. He had searched through all of his scrolls, only finding one left. It had been a few hours since Obito had seen them, so hopefully, the war was still going on and Itachi and Tobi were winning. 

Hidan complained about the lack of food, going through his own scrolls to find nothing. He wasn’t exactly a very organised ninja, as he usually took food pills instead of finding and making packs. With no food pills left, he stared up at the pink sky. 

“I’ll just eat my own hair and nails if needed,” Hidan said, putting his head down on a flat rock. His body was fully functional again, a lot thinner while Jashin’s immortality worked on building muscle back. “Maybe those gross threads of yours too.” 

“You are not eating my body.” 

“I’ll eat that detachable dick of yours then.” 

“I will  _ punch  _ you with that detachable dick of mine, so shut up.” 

The bickering turned into silence not long after, as dehydration had gotten to them both. Hidan found an expired can of lychee drink in a scroll that he hadn’t opened, and it had been there since he was a genin. He opened the can to find it had rotted away and there was black sludge at the bottom. 

He threw it away. 

***

A tall cloaked figure walked towards them in the distance. 

“Hey! Over here!” 

The man came slowly over, hair over one eye and carrying a sword. 

“It’s a Uchiha,” said Kakuzu. “Where is Obito and Itachi?” 

“Dead,” said the man coolly. His voice was a little raspy, possibly from lack of use. “Are you part of Kaguya’s gang?” 

“What the fuck- no. We’ve been here ages. Last saw Tobi a few hours ago, are you also able to get us out?” 

The man didn’t reply. “You need to prove to me you aren’t part of Kaguya’s gang.” 

Hidan looked over at Kakuzu, looking for answers. “Well... we don’t have creepy Hyuuga eyes.”

The man walked past Kakuzu briskly to look at something on the dry, cracked ground. It was Kakuzu’s Akatsuki cloak, in a bundle to use as a makeshift pillow. He picked it up. 

“You’re Sasuke Uchiha,” Kakuzu suddenly remembered. Itachi’s brother, but he thought Itachi’s brother was younger, not older. This man was at least in his thirties. 

Again, he didn’t reply. 

“And you’re Kakuzu and Hidan,” he said finally. He shook out the cloak to look at the red cloud pattern. “The only thing I can do is take you back to Konoha.” 

“Konoha? But we’re in war?” 

“There hasn’t been a war in fifteen years.” 


	4. Velleity

**Velleity **

**_A wish or inclination not strong enough to lead to action._ **

 

****

Hidan’s scythe lay on top of the examining table as he was held in a cell in the Medical Hospital in Konoha. He and Kakuzu went in without whining or complaining, mainly because Kakuzu pointed out that if fifteen years had passed, they didn’t know what advancements in technology there were and therefore, didn’t have an advantage in any situation and may not be able to have another chance of getting out. 

The team in the medical hospital, a mix of integrators and medical ninja, had taken the scythe apart, and their remaining belongings out of all their scrolls. Kakuzu’s cash was examined and then pointed out to his annoyance that due to inflation, the amount of cash on him was worthless. 

Then came the interrogation. 

However, Kakuzu and Hidan did not have anything useful to say, because the Akatsuki had been extinct for fifteen years and they already had information Konoha already knew about. 

They were of course, not going to get out of Konoha without a punishment. In this realm of peacefulness that had settled over the village like a happy cloud, punishment was not a death sentence. The Hokage however, wanted the death sentence, but decided against it as this method of killing enemies was not used anymore. 

Turns out the Konoha’s Hokage was the nephew of a jonin Hidan slaughtered many years ago. He’d forgotten about that.  _ Fucking morons. A life is a life. Get the fuck over it.  _

So in the end, the ‘punishment’ ended up being a put in a rehabilitation centre with other rebellious ninjas.

 

***

 

The centre was on the outskirts of Konoha in the abandoned Uchiha compound. Walls surrounded the building, several metres high and so no one could get out without using chakra. However, there was a sort of chakra shield over it so neither Kakuzu or Hidan could use any jutsu. Sharp objects were taken away and nurses instructed others to not go near the two of them as they were ‘extremely dangerous’. Other than that, they were ordered to get changed into white robes. 

Only by the next hour of sitting in a white room, the people who worked there had started to sound… cultish. 

“ _ This world is peaceful. Nobody fights anymore _ .” 

“ _ The old ways are over. We fight only for love _ .” 

“ _ Any violence is sorted out with the utmost care and peace.”  _

At the back of the centre was a shrine in the garden. The garden was maintained by whoever lived in the centre, who were happy enough to do work. Which, Hidan noticed, after several days of being there, seemed to be all of them. 

Except Kakuzu. 

In the shrine was a sculpture was of a similar copy to the Hokage rock, except the bodies accompanied the heads, each holding up a torch with flames.  _ The Will of Fire  _ was engraved onto each torch. It flickered, and Hidan noticed that bits of smoke would penetrate the chakra shield and melt back into the garden, like bits of cigarette ash. It was nearly night time, and the sunset was making everything glow like fire. 

Kakuzu was sitting under the statue barefoot, reading a book - Hidan rolled his eyes when he approached - on financial updates up to the current year. 

“You think you’re getting out of here to become an accountant or something?” said Hidan, sitting himself down between the legs of the first hokage and Kakuzu. “They put a chakra shield over this place. We’re gonna get out of here looking like goddamn followers of Konoha soon, praying to the shitty Hokage rock each time we mutter a swear word.” 

“Hmm,” Kakuzu’s eyes looked up onto the shrine wall, nodding towards it. Hidan looked up too, to see a security camera. “The camera can hear things too, Hidan.” 

“Whatever. I’m immortal. I’ll end up in here for the next hundred years anyway. You’ll be a pauper with fifteen million ryo, which will only get you a carrot at the store.” 

“True,” Kakuzu agreed. “Unless this is another one of Kaguya’s universes.” 

Hidan moaned. “Oh, fuck off. A universe with food is all I care about.” 

“And getting out of here too is another thing  _ I  _ care about.” 

“Yeah, but how?”

 

***

 

Turns out, the nurses who worked at the centre hadn’t taken away all of Kakuzu’s masks. 

The one left was with his remaining heart, hidden in the caves of the threads that filled Kakuzu. The mask, covered in ancient stitching and looked a bit like a duck, poked out of his back, nosing itself out like mole buried in dirt. 

Kakuzu slumped over onto Hidan’s leg as the mask shot out into a monster and threw itself onto the glassy ceiling where the wispy ashes of the hokage torch went up to. 

The effect was instantaneous. The chakra shield was released immediately as it seemed to crack under the intensity of the masked monster crashing into it. 

The chakra filled up Hidan like a bubble of energy and he took Kakuzu’s body and jumped up. The monster shot back into Kakuzu and he regained consciousness. 

“So long, fuckers!” 

The people in the garden stopped and looked as if they wanted to escape too. A medical ninja shot out rope from her hand, but Hidan dodged it. 

With that, Hidan wanted to take his lovers hand and go off into the sunset, but Kakuzu swiped it away for a moment. “Come on!” 

Several hand signs later, there was large bangs and crashes as the confiscated masks appeared from the medical building where they were last detained at. They joined Kakuzu and Hidan as old friends. 

“Now can we hold hands and go into the sunset? Become missing nins for ever and ever?” 

“Fine.” 

With that, all five masks took aim and striked at Konoha; it wasn’t long before a small patch of the town was set on fire. 

They ran off, Hidan ahead of Kakuzu. Originally they were going to run into the sunset like what happens in romantic movies, just as Hidan asked him before, but that was a bad idea as they were ninjas and needed to see everything around them instead of being blinded. 

***

They had ran for several days. Somewhere near River Country, where there was a hideout only the Akatsuki could get to. 

They decided to wait till morning to go in; if they missed the entrance then there would be several million paper bombs exploding around them for a long time and they would be shredded to bits. 

To get into the hideout, two Akatsuki members would put their hand and ring onto a rock. The rock would recognise the DNA and the ring. However, the hideout was huge. 

Hidan was literally standing on one of Kakuzu’s monsters, peering into every rock, being careful not to touch any of them, which there were thousands of them. The only difference in the rocks was there was a small symbol of the Hidden Rain on two of them. Kakuzu found the one on the left hand side within a few minutes; then him and Hidan scoured the area for an hour on the right. 

Finally, their hands were placed on the rocks and the hideout opened up into a little cave.

 

***

 

A little stream of water trickled through the cave; it smelled of dirt and moss. Cracks of sunlight shifted through the rocks. However, that wasn’t what got Kakuzu’s attention. 

“Hidan,” he said, picking up something from the ground. Hidan squinted through the darkness to see a scroll. He unrolled it, then lit up a stake with a fire jutsu to see what was written on it. 

“What is it? Hate mail?” 

There was a pause. “It’s Orochimaru’s Retrieval Jutsu.” 

Something that felt like happiness started to fill Hidan. “What does that mean?” 

“It means,” said Kakuzu, clearing his throat a little, “We can have the Akatsuki back.” 

“Wait, really?” 

“Well,” said Kakuzu, putting the scroll on the floor and flattening it out, “We’re on the run in what feels like a different world. Even though it’s  _ our  _ world. What are we supposed to do for the rest of our lives?” 

“Fight and fuck?” Hidan suggested. 

Kakuzu looked annoyed. “Besides that.” 

“...Fuck and fight?” 

“Shut up - the Akatsuki gives us something to fall back on. As much as you didn’t like them, it gave us something to do in our pathetic missing nin lifestyle. It also had good money.” 

Hidan thought about it for a moment. He looked down at the scroll. Scientific notes were written in gibberish, but he recognised a summoning seal in the middle of the document. He looked up, and Kakuzu nodded at him. 

Both of them bite their thumbs, enough for a drop of blood. At once, the places were the deceased Akatsuki members would have their meetings flickered… 

They were suddenly around their old friends. 

Tears unknowingly filled Hidan’s eyes. Pain, Konan, Deidara, Kisame, Itachi, Sasori, Tobi… 

“Welcome... welcome back, guys.” 


End file.
